Sniffer

25class Sniffer26{27    /**28     * File object29     *30     * @var File|Response31     */32    public $file;33 34    /**35     * Create an instance of the class with the input file36     *37     * @param File|Response $file Input file38     */39    public function __construct(/* File */ $file)40    {41        if (!is_object($file) || !$file instanceof Response) {42            // For BC we're asking for `File`, but internally we accept every `Response` implementation43            throw new InvalidArgumentException(sprintf(44                '%s(): Argument #1 ($file) must be of type %s',45                __METHOD__,46                File::class47            ), 1);48        }49 50        $this->file = $file;51    }52 53    /**54     * Get the Content-Type of the specified file55     *56     * @return string Actual Content-Type57     */58    public function get_type()59    {60        $content_type = $this->file->has_header('content-type') ? $this->file->get_header_line('content-type') : null;61        $content_encoding = $this->file->has_header('content-encoding') ? $this->file->get_header_line('content-encoding') : null;62        if ($content_type !== null) {63            if ($content_encoding === null64                && ($content_type === 'text/plain'65                    || $content_type === 'text/plain; charset=ISO-8859-1'66                    || $content_type === 'text/plain; charset=iso-8859-1'67                    || $content_type === 'text/plain; charset=UTF-8')) {68                return $this->text_or_binary();69            }70 71            if (($pos = strpos($content_type, ';')) !== false) {72                $official = substr($content_type, 0, $pos);73            } else {74                $official = $content_type;75            }76            $official = trim(strtolower($official));77 78            if ($official === 'unknown/unknown'79                || $official === 'application/unknown') {80                return $this->unknown();81            } elseif (substr($official, -4) === '+xml'82                || $official === 'text/xml'83                || $official === 'application/xml') {84                return $official;85            } elseif (substr($official, 0, 6) === 'image/') {86                if ($return = $this->image()) {87                    return $return;88                }89 90                return $official;91            } elseif ($official === 'text/html') {92                return $this->feed_or_html();93            }94 95            return $official;96        }97 98        return $this->unknown();99    }100 101    /**102     * Sniff text or binary103     *104     * @return string Actual Content-Type